It is known to use foamed milk in the preparation of beverages such as cappuccino coffee. Traditionally foamed milk has been produced by using a steam wand to direct a steam jet into a reservoir of milk. This is still the primary method of producing foamed milk in a commercial environment. It is desirable to be able to prepare cappuccino-style beverages in the home. However, it is inconvenient to use steam jet equipment in the home since it can be dangerous if not used correctly and can be difficult to clean. This is particularly disadvantageous for equipment used with milk which requires thorough cleaning to prevent contamination.
A cartridge for a domestic beverage machine which is suitable for producing foamed milk is known from EP 1 716 055. Foamed milk is produced within the cartridge by causing air to become entrained in a stream of milk. It is an object of the present invention to provide an improved cartridge for producing foamed beverages, particularly foamed dairy-based beverages.